1. Technical Field
Exemplary aspects of the present disclosure generally relate to an image forming apparatus, such as a copier, a facsimile machine, a printer, or a multi-functional system including a combination thereof, and more particularly to, an image forming apparatus including a cleaning device for cleaning a secondary transfer device.
2. Description of the Related Art
In known electrophotographic image forming apparatuses, a photosensitive member, a developing device, a cleaning device for cleaning the photosensitive member, and so forth are assembled as a single unit, known as a process cartridge, and the process cartridge is detached from and attached to a main body of the image forming apparatus in the case of paper jams and during maintenance.
In such a process cartridge, toner tends to leak easily from an area in which toner moves, such as between a developing roller of the developing device and the photosensitive member, and between a cleaning blade of the cleaning device and the photosensitive member. In order to prevent the leakage of toner, in general, a seal member is provided to the area in which toner moves. In order to enhance sealing capabilities, a known approach includes two sets of seal members. Such a configuration is proposed, for example, in JP-2000-132028-A.
In another approach, an amount of contact of the seal member relative to the photosensitive member is made adjustable. Such a configuration is proposed, for example, in JP-H10-48945.
After extended use, in the process cartridge, degradation of the seal member and a part that contacts the seal member, or an accumulation of toner on the seal member reduces the sealing capabilities of the seal member. As a result, toner leaks undesirably from the sealed portion in the process cartridge upon attachment and detachment of the process cartridge relative to the main body of the image forming apparatus.
Such leakage of toner contaminates an intermediate transfer belt with the toner. The toner adhered to the intermediate transfer belt moves to a secondary transfer roller in the subsequent imaging process, contaminating the secondary transfer roller and then a rear surface of the recording medium. In order to prevent such difficulty, the known sealing reinforcements as described above may be employed. However, the know approaches require an increase in the number of parts and complicate an overall configuration, thereby increasing the cost.
In recent years, in order to accommodate growing market demand for better image quality, the diameter of toner particles is reduced, and a degree of sphericity is increased. The fluidity of toner of this kind is enhanced as compared with standard toner. Thus, leakage of such toner is difficult to prevent with the known seal members upon detachment and attachment of the process cartridge, resulting in the contamination of a recording medium.
In view of the above, there is thus an unsolved need for an image forming apparatus capable of preventing contamination of a recording medium with toner upon detachment and attachment of the process cartridge.